The invention is based on a device for connecting vibrating components that have different electrical potentials, in particular for connecting a stator housing for an electric motor with a housing for control electronics inside a clutch actuator of a motor vehicle.
A clutch actuator for engaging and disengaging a motor vehicle clutch is made known in DE 197 01 739 A1, which said clutch actuator has an elongated electric motor that is controlled by control electronics. The electric motor and the control electronics are subjected to vehicle vibrations, whereby particularly strong vibrations are induced when the clutch actuator is mounted directly on the gearbox. As a result, a mechanical connection between such components must be fatigue-resistant in design. Moreover, the electric motor and the control electronics are current-carrying radio-interference sources that produce electromagnetic fields and influence each other as well as other electrical components of the motor vehicle. For example, the stator housing of the electric motor has a different electrical potential than the housing in which the control electronics are contained, so that the difference in potential causes an electromagnetic field to be radiated. For this reason, such components must be designed so that they are electromagnetically compatible with each other and with other components.
Since the transfer of force between the two components takes place essentially only by means of the plastic ring, the device according to the invention has the advantage that, by pressing the plastic ring between the attachment segment and the opening, a connection having sufficient static stiffness can be produced, on the one hand and, on the other, dimensional equalization can occur as a result of the remaining residual elasticity of the plastic material, by way of which a fatigue-resistant connection is ensured.
Moreover, due to the relatively high dynamic resilience of plastic, the two components are largely decoupled from each other in terms of vibrations, i.e., transfers of structure-borne noises between the components are prevented. In general, the damping of a machine design consisting of individual components results primarily from the damping occurring at the interconnect points of individual components. It is commonly known that plastic material has good damping properties; this is why resonance resiliences produced by externally-caused vibrations can be reduced by means of the plastic ring.
The electrical contact means bridge the gap between the radially outer circumferential surface of the attachment segment and the radially inward circumferential surface of the opening in which the plastic ring is pressed, and therefore act to equalize potentials between the components and, as a result, provide electromagnetic compatibility between said components and between themselves and other components.
Finally, the combination, according to the invention, of the plastic ringxe2x80x94that establishes the mechanical connection and transfers forcexe2x80x94with the electrical contact means can be realized in a single assembly step, i.e., by inserting the attachment segment of the one component into the opening of the other component, while simultaneously establishing a mechanical and electrical connection.
A particularly preferred further development of the invention provides that the first component contains a mounting plate composed of an electrically conductive material, e.g., aluminum die casting, and a housingxe2x80x94that is mounted to one end of said mounting plate and is also electrically conductivexe2x80x94for the control electronics of a clutch actuator for engaging and disengaging a motor vehicle clutch and, on the other end of the mounting plate, the opening is formed in a collar. The second component contains an electric motor of the clutch actuator that has a stator housing composed of electrically conductive material. The housing that contains the control electronics and the stator housing are advantageously located close together and parallel to each other on the same side of the mounting plate. As a result of the equidirectional arrangement, the elongated electric motor and the control electronics form a particularly compact unit that can be located in the clutch actuator housing in space-saving fashion.
According to a further development, the electrical contact means contain a ring formed on a radially inner circumferential surface of the opening of the mounting plate, which said ring has peripherally-separated blades located around at least part of the circumference of the opening and extending radially inwardly, each of which said blades is outfitted with a thin pinching rib on its exposed end, which said pinching rib can be brought to bear against the outer circumferential surface of the attachment segment while the attachment segment is inserted in the opening and, as a result, it can be compressed by a small amount in the radial direction. Due to the resultant elastic and/or plastic deformation of the pinching ribs, a reliable, electrically conductive contact is established, so that a low-ohmic connection is produced.